In recent years, a satellite communication system using a vent pipe type HTS (High Throughput Satellite) has been put to practical use in a multi-beam satellite communication system using broadband Ka band. However, in a vent pipe type relay satellite, since frequency bandwidth to be allocated to each beam area is fixed in advance, even when a request to change the frequency bandwidth allocated to each beam area is generated depending on change in communication demand on a ground side after satellite launch, it cannot be changed. Because of this, in a case of the vent pipe type relay satellite, frequency utilization efficiency and system throughput may be reduced.
In contrast, a relay satellite equipped with a channelizer can change the frequency bandwidth allocated to each beam area even after the satellite launch and has flexibility according to changes in communication demand on the ground side. Therefore, by using the channelizer, it is possible to maintain high throughput of the satellite communication system from immediately after the satellite launch to dozen years later when lifetime of the satellite runs out.
The type of the channelizer is roughly divided into two of an analog type and a digital type.
An analog type channelizer (analog channelizer) is a system which realizes a band tuning to be allocated to each beam area by an analog circuit, and is disclosed in, for example, Patent Literature 1 and Patent Literature 2 below.
On the other hand, a digital type channelizer (digital channelizer) is a system which realizes the band tuning to be allocated to each beam area by a digital circuit, and is disclosed in, for example, Patent Literature 3 below.